Gang-saw mill



(No Model.)

DE WITT C. PRESGOTT.

GANG SAW MILL.

17726-172107 my wwf/a 72;@560/-- a i A,

UNITED STATES DE VITT CLINTON PRESCOTT,

OF MARINEITE, VISGOSIN.

GANG-SAW MILL.

SPECIFICATION forming part of Letters Patent No. 296,618, dated April 8, 1884.

(No model.)

fo all whom t may concern.-

Be it known that I, DE WITT C. Pnnscorr,

a citizen of the United States, and residing at Marinette, in the county of Marinette and State of Wisconsin, have invented a certain new and useful Improvement in an Oscillating Mechanism for Gang-Saw Mills, which is fully set forth in the following specification, reference being had to the accompanying drawings, in whichv Figure l represents a side elevation of a portion of the saw-mill frame, the sash or sawgate, and my oscillating mechanism applied thereto 5 Fig. 2, a vertical section of the` same taken on the line x x, Fig. l; and Fig. 8, a plan section of the same taken on the line y y, Fig. l.

My present invention relates to mechanism for oscillating the saw gate or sash in gang-saw mills. This movement of the gate is well known and in quite general use, whereby at the end of the downstroke the gate is thrown backward to clear the teeth of the saws, and at the end oi' the upstroke thrown forward to be brought into working position. Anumber of devices have been applied for this purpose.

This invention consists in a novel mechanism for accomplishing this old and well-known movement of the saw-gate by which I believe I have accomplished some desirable advantages.

I will proceed to describe in det-ail the construction and operation of my present invention, and will then point out definitely in the claim the said improvements which I believe to be new and wish to protect by Letters Patent.

In another application of even date herewith I have shown and described this mechanism applied to a gang-saw mill, fully shown and described inail its parts; but the oscillat-v ing mechanism as a separate improvement is disclaimed as a part ol' the invention set out in the said application. In the present case I have shown the oscillating mechanism applied in substantially the same way as in the gang-saw application referred to; but I have shown in the drawings only so much of the mill asis necessary to illustrate the construction, application,and operation 0f the invention included in my present application,which is restricted to the oscillating mechanism and does not include any other part of the machine. Vhile the oscillating mechanism in this case is shown constructed and applied to a gate and frame substantially the same as in the companion application referred to above, l wish it to be distinctly understood that I do not limit the invention to this particular application, for the oscillating mechanism constituting the presentimprovement may be ap pliedto gang-saw mills of almost any construetion; and therefore I wish to be understood as claiming this improvement, broadly, without reference to the particular construction and arrangement ofthe other parts of the mill.

In the accompanying drawings, A represents a portion of one of the side pieces of the upright frame of the mill, or some suitable portion of the side frame which will provide for the attachment of the parts hereinafter mentioned. Xear the upper portion of this side piece there is a circular opening,a around which is a boss, a', so that this opening is adapted to form a journal-bearing. A plate or strong bar, B, is provided near its upper end with a boss, b, fitted to the opening a in the side piece, and constituting a trunnion or journal for the piece B when the two parts are fitted together, as shown in Fig. 2 ofthe drawings. Any suitable device may be employed to secure the plate B in position. I have shown a cap, C, arranged on the outside of the bearing in the side piece, fitting over the latter, and fastened to the hub b by means of a screw, c. It will be understood of course that one of these plates B is attached to each side piece inside of the upright frame, and they constitute the supporting-pieces in which the sawgate is mounted,as will now be described. These plates are not secured to the main frame at their lower ends, but are free to swing back and forth on their trunnions. The guide-boxes, or slide-boxes, as they are sometimes called, are attached to the swinging plates, the upper ends, D, being near the upper end, and the lower ends, E, near the lower end, of the-respective plates. These boxes are preferably of rectangular form, as shown in Fig. 3 of the drawings, and are preferably provided with linings d @,of bronze or vulcanized riber,though this lining is not a material part of this invention.

rIhe stiles F of the saw gate or sash are mounted directly in the guide-boxes on the swinging plates, and so constitute the gatelslidesgvhich are usually made separate pieces and project downward from the stiles.

Now it is evident from this description that the swinging of the guide-plates will swing the saw gate or sash in like manner and effect the necessary oscillation to clear the saws and bring them into proper working position again. In order to eff'ect this movementIprovidearockshaft, G,which may be arranged in rca-r of the saw-gate, and connect this rock-shaft to the lower end of the respective swinging plates by means of a pitman, I'I, and a crank-arm, g, on the rock-shaft. The required movement ol' theq rock-shaft is obtained byproviding-it with another crank-arm, g', to which is connected an eccentric-rod, I, the strap t of which surrounds an eccentric or cam, J, on a shaft, K, all these parts being necessarily timed, so that the revolution of this last shaft will oscillate the rockK shaft at the proper intervals and in the proper directions to swing the saw-gate backward at the close of its backward stroke and forward at the close of its upward stroke. In the drawings, the shaft on which the drivingeccentric is mounted is the main shaft, as the mechanism is shown applied to the special machine set forth in my other application, heretofore mentioned, in which the main shaftis arranged on the same floor as the frame. This particular arrangement, therefore, is not essential to my present improvement, for it is obvious that it may be ap plied-to any millin which asaw-gate is used, it being necessary to provide a suitable shaft to which the cam or eccentricis applied for oscillating the rock-shaft, if it is desired to use this device. I wisn to be understood, therefore, as intending to include in my improvement the application ofrmy mechanism to any saw-mill where it can be used.

It is also evident that the oscillation of the swinging plates in which the gate is mounted is not dependent upon the particular mechanism herein described and shown for accomplishing this movement, but some other device may be substituted for the cam, or some other suitable device for the rock-shaft and pitmamwithout materially modifying my improvement,

hence I do not wish to be understood as limiting my invention to these particular devices for imparting the required motion to the swing ing plates.

It will be seen that the center of motion of the swinging plates is very near the upper p0rtion of the gate when atits lowest point; hence the backward oscillation of the plat-es will entirely clear the saws, and I am enabled to effeet this necessary clearing by a single oscillation, instead of the double oscillation sometimes used.

Instead of arranging the stiles of the gate directly within the guide-boxes, the guide-boxes may be attached to the stiles as usual and arranged in the guides; but by the particular arrangement described and shown I am enabled to secure the advantage of diminishing the width of the saw-'frame and also simplifying and cheapening the construction of the mill.

rIhe guides may be placed on the swinging plates and the guide-boxes on the gate, and yet the result will be substantially the same so far as the main ffeatures of my improvement are concerned.

I-Iaving thus described my invention, whatI claim as new, and desire to secure by Letters Patent, is-

lThe combination, with the main frame, of swinging plates jou rnaled in said frame, guideboxes D E, placed in line upon said plates, stiles F, sliding directly in both of such guides, and operating mechanism, substantially as described.

DE wirr oLmfroN riansco'rr.

Vitnesses: Y JOHN J. ANDREW, BrouT B. PENNELL. 

